Perhaps you should try some spelling variations:
toc sac » toc sach, toc san, hoc sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
sac ky » cac ky, sai ky
ve cua » le cua, te cua, ve cum
bao va » bao ve, ban va, cao va
di cua » dai cua, doi cua, do cua
de cua » le cua, te cua, dieu cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky nang xa hoi. hieu ve cua ((bao va) OR (tao va)) hanh ((di cua) or (de cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky nang xa hoi. hieu ve cua ((bao va) OR (tao va)) hanh ((di cua) OR (de cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky nang xa hoi. hieu ve cua ((bao va) OR (tao va)) hanh ((di cua) or (de cua)) triet".
• Adding a wildcard symbol may retrieve word variants: toc sac ky nang xa hoi. hieu ve cua ((bao va) OR (tao va)) hanh ((di cua) or (de cua)) triet*.